The present invention relates generally to medication infusion devices, and more particularly to a miniature extracorporeal medication infusion device for precisely and conveniently dispensing controlled quantities of a liquid medicine into a human or animal body.
Liquid medications (which, for purposes of this patent application, means any liquid that is to be injected into a human or animal body for therapeutic or diagnostic purposes) have been traditionally administered by a hypodermic syringe. If multiple doses of the liquid medication are required, the multiple doses are typically administered at timed intervals of several days or several hours.
More recently, it has been recognized that the benefits of certain liquid medications may be enhanced by administering the liquid medication in extremely small dosages on a frequent basis. Medication infusion devices which have been designed for this purpose are disclosed in U.S. Pat. Nos. 4,191,181, 4,150,672, 4,215,689, and 3,858,581. Additionally, other devices have been provided which administer a constant flow rate of liquid medication, such as shown in U.S. Pat. No. 4,201,207.